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The level of SMM in malt is responsible for the DMS level in wort. During mashing the SMM, DMS and very soluble DMSO are brought into solution. No SMM is hydrolized to DMS at this time. | The level of SMM in malt is responsible for the DMS level in wort. During mashing the SMM, DMS and very soluble DMSO are brought into solution. No SMM is hydrolized to DMS at this time. | ||
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TABLE III | TABLE III | ||
Revision as of 11:25, 29 September 2007
DIMETHYL SULFIDE (DMS)
The perceived flavor intensity can be expressed as follows where P is the perceived flavor intensity, C is a concentration of DMS in beer, and T is the taste threshold in beer:2
P = (beer style constant) = ( C/T ) n
The level of DMS in unmalted barley, wheat, rye and corn syrup is negligible.
The amount of DMS in corn grits has been reported to be approximately 0.4 ppb.1
Essential oils of hops contain small levels of DMS but are steam stripped from the boiling wort.5
Some typical levels of DMS and SMM in different varieties of malt are shown in Table IV.4
The level of SMM in malt is responsible for the DMS level in wort. During mashing the SMM, DMS and very soluble DMSO are brought into solution. No SMM is hydrolized to DMS at this time.
TABLE III DMS and SMM LEVELS in TYPICAL MALTED BARLEY KERNEL MALT KERNEL DMS (ppb) SMM (ppb) 1) Husk 0.81 0.67 2) Starchy Endosperm 1.5 1.2 3) Embryo and Scutellum 5.9 2.2 4) Crospire 15.0 14.0
- (Biosynthesis activity 2-4)
TABLE IV REPORTED DMS and SMM LEVELS in DIFFERENT MALT VARIETIES MALT KERNEL DMS (ppb) SMM (ppb) SMM (ppb)
- Larken 12.9 12.0 24.9
- Proctor, Pale Ale 7.1 3.7 10.8
- Klages (2 row) 9.2 2.0 11.2
- U.S. Malt: (high modification, low kilning temperature)
- British Malt: (moderate modification, higher kilning temperature)
An American maltster reported that typical combined DMS/SMM levels in North American brewers malt averaged 10-15 ppb. But during years of high protein levels, for example the '88 drought, levels may approach 20 ppb.
TABLE V SMM LEVELS in MALT vs. DMS in FINISHED LAGER BEER MALT BEER % INCREASE
SMM (ppb) DMS (ppb) (SMM to DMS) 3.2 38.0 1090 4.6 61.0 1200 6.0 78.0 1200 8.4 98.0 1070
TABLE VI REACTIONS CONTRIBUTING TO DMS FORMATION
(CH3)2S-CH2-CH2-CH(NH2)-COOH(CH3)2 + OH >(CH3)2S<(oxidation/reduction)>(CH3)2S=O S-Methyl methionine Dimethyl sulfide Dimethyl Sulfoxide SMM DMS DMSO
Infromation from http://www.abtonline.com
